Systems for supporting data communication cables in buildings housing large amounts of computer equipment are known in the prior art. Some of these prior art systems include rows of cable-supporting brackets suspended from rails attached to the underside of the roof of the building. The rows of brackets hang over rows of server racks and other data-processing equipment. Each of the brackets is shaped like an inverted “T”, where the stem corresponds to a vertical support member, and the two sides of the hat of the inverted “T” correspond to a pair of opposing support arms for supporting cable trays on either side of the vertical support member. In operation, the vertical support members of the brackets are mounted on the overhead-mounted rails. Next, cable tray sections are mounted on the opposing support arms to form two, parallel cable trays on either side of each row of brackets. In systems having a height-adjustable mechanism, the height of each row of brackets is made to be as uniform as possible so that the adjoining edges of the tray sections are mutually aligned. Finally, the communication cables are lifted up, laid into, and sometimes pulled along the cable trays to properly position them. Such cable support systems are often used in data centers housing rows of server racks or other data-processing equipment.